FR2925005A3 - Tire and ground adhesion estimating method for controlling stability of motor vehicle during turning, involves selecting calculating model corresponding to determined situation of vehicle, and calculating adhesion of vehicle based on model - Google Patents
Tire and ground adhesion estimating method for controlling stability of motor vehicle during turning, involves selecting calculating model corresponding to determined situation of vehicle, and calculating adhesion of vehicle based on model Download PDFInfo
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- FR2925005A3 FR2925005A3 FR0759841A FR0759841A FR2925005A3 FR 2925005 A3 FR2925005 A3 FR 2925005A3 FR 0759841 A FR0759841 A FR 0759841A FR 0759841 A FR0759841 A FR 0759841A FR 2925005 A3 FR2925005 A3 FR 2925005A3
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
- B62D6/002—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels
- B62D6/006—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels using a measured or estimated road friction coefficient
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
- B60T8/17—Using electrical or electronic regulation means to control braking
- B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
- B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
- B60W40/06—Road conditions
- B60W40/068—Road friction coefficient
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N19/00—Investigating materials by mechanical methods
- G01N19/04—Measuring adhesive force between materials, e.g. of sealing tape, of coating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2210/00—Detection or estimation of road or environment conditions; Detection or estimation of road shapes
- B60T2210/10—Detection or estimation of road conditions
- B60T2210/12—Friction
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2230/00—Monitoring, detecting special vehicle behaviour; Counteracting thereof
- B60T2230/02—Side slip angle, attitude angle, floating angle, drift angle
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
- B60T2270/00—Further aspects of brake control systems not otherwise provided for
- B60T2270/86—Optimizing braking by using ESP vehicle or tire model
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W2050/0001—Details of the control system
- B60W2050/0019—Control system elements or transfer functions
- B60W2050/0028—Mathematical models, e.g. for simulation
- B60W2050/0031—Mathematical model of the vehicle
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W50/00—Details of control systems for road vehicle drive control not related to the control of a particular sub-unit, e.g. process diagnostic or vehicle driver interfaces
- B60W2050/0001—Details of the control system
- B60W2050/0019—Control system elements or transfer functions
- B60W2050/0028—Mathematical models, e.g. for simulation
- B60W2050/0031—Mathematical model of the vehicle
- B60W2050/0033—Single-track, 2D vehicle model, i.e. two-wheel bicycle model
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- Mechanical Engineering (AREA)
- Physics & Mathematics (AREA)
- Transportation (AREA)
- Mathematical Physics (AREA)
- Chemical & Material Sciences (AREA)
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- Automation & Control Theory (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
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- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Control Of Driving Devices And Active Controlling Of Vehicle (AREA)
Abstract
Description
PROCEDE D'ESTIMATION DE L'ADHERENCE D'UN VEHICULE AUTOMOBILE ET DISPOSITIF CORRESPONDANT. METHOD FOR ESTIMATING THE ADHESION OF A MOTOR VEHICLE AND CORRESPONDING DEVICE
La présente invention concerne le domaine des 5 véhicules automobiles. Afin de contrôler de manière fiable la stabilité d'un véhicule automobile, en particulier en virage, il est nécessaire de déterminer l'adhérence, ou coefficient de friction compris entre 0 et 1, entre les pneumatiques 10 de celui-ci et le sol. Aussi, plus précisément, l'invention concerne un procédé d'estimation de l'adhérence d'un véhicule automobile comprenant une étape consistant à établir la valeur d'au moins un paramètre compris dans l'ensemble 15 comprenant au moins la vitesse longitudinale, l'angle de roues, l'accélération transversale, et la dérive du véhicule automobile. A partir de ces paramètres, il est connu d'en déduire la valeur de l'adhérence dudit véhicule 20 automobile, par exemple par l'utilisation du modèle dit bicyclette. Classiquement, on compare les données calculées par ce modèle à celles mesurées sur le véhicule automobile pour en déduire l'adhérence dudit véhicule automobile. 25 Toutefois, dans certaines situations, les données calculées par le modèle bicyclette peuvent être incohérentes avec celles mesurées sur le véhicule automobile, ce qui peut poser des problèmes en particulier dans le cas de systèmes pilotés visant à 30 appliquer une force de freinage déterminée en fonction de l'adhérence estimée. The present invention relates to the field of motor vehicles. In order to reliably control the stability of a motor vehicle, in particular when cornering, it is necessary to determine the adhesion, or coefficient of friction, between 0 and 1, between the tires 10 of the latter and the ground. Also, more specifically, the invention relates to a method for estimating the adhesion of a motor vehicle comprising a step of establishing the value of at least one parameter included in the assembly comprising at least the longitudinal speed, the wheel angle, the transverse acceleration, and the drift of the motor vehicle. From these parameters, it is known to deduce the value of the adhesion of said motor vehicle, for example by the use of the so-called bicycle model. Conventionally, the data calculated by this model are compared with those measured on the motor vehicle to deduce the adhesion of said motor vehicle. However, in certain situations, the data calculated by the bicycle model may be inconsistent with those measured on the motor vehicle, which may be problematic in particular in the case of controlled systems for applying a determined braking force according to the invention. the estimated adhesion.
La présente invention a pour but de remédier à ces inconvénients en proposant une solution particulièrement fiable et relativement simple à mettre en oeuvre puisqu'elle nécessite un nombre relativement faible de capteurs à mettre en oeuvre. Avec cet objectif en vue, le procédé selon l'invention, par ailleurs conforme au préambule cité ci-avant, est essentiellement caractérisé en ce qu'il comprend en outre les étapes consistant à : - déterminer à partir de la valeur du(des) paramètre(s) établi(s) la situation dans laquelle se trouve le véhicule automobile parmi un ensemble d'au moins une première et une deuxième situations, -sélectionner un modèle de calcul de l'adhérence 15 du dit véhicule automobile correspondant à la situation déterminée, et - calculer l'adhérence dudit véhicule automobile en fonction du modèle sélectionné. Dans un mode de réalisation, on détermine la valeur 20 de la dérive du véhicule automobile, et si la valeur de la dérive déterminée est supérieure à un premier seuil, on considère que le véhicule automobile est en situation de dérive pure et l'adhérence est calculée par un modèle de frottement dans lequel l'adhérence Mu répond à 25 l'équation suivante : JGammal2 + Gammat2 Mu = Gammat max Où Gammat, Gammat max et Gammal sont respectivement l'accélération transversale, l'accélération transversale 30 maximale, et l'accélération longitudinale du véhicule. The present invention aims to overcome these disadvantages by providing a particularly reliable and relatively simple to implement since it requires a relatively small number of sensors to implement. With this objective in view, the method according to the invention, furthermore in accordance with the preamble cited above, is essentially characterized in that it further comprises the steps of: determining from the value of parameter (s) established (s) the situation in which the vehicle is located among a set of at least a first and a second situations, -selecting a model for calculating the adhesion 15 of said motor vehicle corresponding to the situation determined, and - calculate the adhesion of said motor vehicle according to the selected model. In one embodiment, the value of the drift of the motor vehicle is determined, and if the value of the drift determined is greater than a first threshold, it is considered that the motor vehicle is in a pure drift situation and the adhesion is calculated by a friction model in which the adhesion Mu responds to the following equation: JGammal2 + Gammat2 Mu = max Gammat Where Gammat, Gammat max and Gammat are respectively transverse acceleration, maximum transverse acceleration, and longitudinal acceleration of the vehicle.
Dans un mode de réalisation, on détermine la valeur de la vitesse de braquage des roues, et/ou l'accélération transversale et l'angle de braquage des roues ; et si la vitesse de braquage des roues est supérieure à un deuxième seuil, ou si le signe de l'accélération transversale est opposé au signe de l'angle de braquage des roues, on considère que le véhicule automobile est en situation transitoire, et l'adhérence est calculée par un modèle continu dans lequel Mu(t) = Mu(t-1), où Mu(t) est l'adhérence instantanée au temps Mu (t) . Selon un autre aspect de l'invention, on détermine les valeurs suivantes . V la vitesse longitudinale du véhicule automobile, Seuil3, seuil4, et seuil5 respectivement un troisième, quatrième et cinquième seuil, Gammat bicyclette l'accélération transversale calculée par un modèle bicyclette, et Gammat mesuré l'accélération transversale ; et dans les cas suivants . si V < seuil3 , ou si Gammat bicyclette < seuil4 et Gammat mesuré < seuil5*Mu(t-1), on considère que le véhicule automobile est en situation de limite et l'adhérence est calculée par un modèle constant dans lequel la valeur de l'adhérence (Mu) est fixée à 1. Selon un autre aspect de l'invention, si le véhicule automobile ne peut pas être considéré comme dans l'une des situations précédentes, l'adhérence (Mu) est calculée par un modèle de maximum défini par Mu = max(mu bicyclette, mu mobilisée) Où mu bicyclette et mu mobilisée sont les valeurs de l'adhérence calculée respectivement par le modèle bicyclette et l'adhérence mobilisée Mu JGammal2 + Gammat2 Gammat max Selon un autre de ses objets, l'invention concerne un dispositif susceptible de mettre en oeuvre le procédé selon l'invention, et comprenant au moins l'un des éléments suivants . - un bloc de calcul de l'adhérence selon un modèle bicyclette, et dont au moins deux entrées sont la vitesse longitudinale et l'angle de roues, du véhicule automobile, - un deuxième bloc de calcul de l'adhérence dite mobilisée selon un modèle de frottement et dont au moins deux entrées sont l'accélération longitudinale et l'accélération transversale du véhicule automobile, - un troisième bloc configuré pour assigner la valeur constante 1 comme valeur de l'adhérence, - un quatrième bloc configuré pour déterminer la situation dans laquelle se trouve le véhicule automobile et dont au moins quatre entrées sont la vitesse longitudinale, l'angle de roues, l'accélération longitudinale, et l'accélération transversale du véhicule automobile, - un bloc configuré pour calculer le maximum entre la valeur de l'adhérence calculée par le modèle bicyclette et la valeur de l'adhérence calculée par le modèle de frottements, et - un bloc de calcul pour assigner, en fonction de la détermination de la situation dans laquelle se trouve le véhicule automobile, la valeur de l'adhérence Mu appropriée comprise dans l'ensemble : Mu(t) = Max(Mu mobilisé, Mu bicyclette), Mu(t) = Mu bicyclette, Mu(t) = Mu(t-1), et Mu(t) = 1. In one embodiment, the value of the steering speed of the wheels, and / or the transverse acceleration and the steering angle of the wheels is determined; and if the steering speed of the wheels is greater than a second threshold, or if the sign of the transverse acceleration is opposite to the sign of the steering angle of the wheels, it is considered that the motor vehicle is in a transient state, and Adhesion is calculated by a continuous model in which Mu (t) = Mu (t-1), where Mu (t) is the instantaneous adhesion to time Mu (t). According to another aspect of the invention, the following values are determined. V the longitudinal velocity of the motor vehicle, Threshold3, threshold4, and threshold5 respectively a third, fourth and fifth threshold, Gammat bicycle cross acceleration calculated by a bicycle model, and Gammat measured transverse acceleration; and in the following cases. if V <threshold3, or if Gammat bicycle <threshold4 and Measured gamma <threshold5 * Mu (t-1), we consider that the motor vehicle is in limit situation and the adhesion is calculated by a constant model in which the value of the adhesion (Mu) is set at 1. According to another aspect of the invention, if the motor vehicle can not be considered as one of the preceding situations, the adhesion (Mu) is calculated by a model of maximum defined by Mu = max (mu bicycle, mobilized mu) Where mu bicycle and mu mobilized are the values of the adhesion calculated respectively by the bicycle model and the mobilized adhesion Mu JGammal2 + Gammat2 Gammat max According to another of its objects, the invention relates to a device capable of implementing the method according to the invention, and comprising at least one of the following elements. - a calculation block of the adhesion according to a bicycle model, and of which at least two entries are the longitudinal speed and the wheel angle, of the motor vehicle, - a second block of calculation of the adhesion called mobilized according to a model of friction and of which at least two entries are the longitudinal acceleration and the transverse acceleration of the motor vehicle, - a third block configured to assign the constant value 1 as the value of the adhesion, - a fourth block configured to determine the situation in which is the motor vehicle and of which at least four entries are the longitudinal speed, the wheel angle, the longitudinal acceleration, and the transverse acceleration of the motor vehicle, - a block configured to calculate the maximum between the value of the adhesion calculated by the bicycle model and the value of the adhesion calculated by the friction model, and - a calculation block for assigning, in operation the determination of the situation in which the motor vehicle is located, the value of the appropriate Mu grip included in the set: Mu (t) = Max (Mu mobilized, Mu bicycle), Mu (t) = Mu bicycle , Mu (t) = Mu (t-1), and Mu (t) = 1.
De préférence, le bloc de calcul de l'adhérence selon un modèle bicyclette comprend en outre une autre 10 entrée intégrant l'inertie du véhicule automobile (Mz appliqué). Avantageusement, on peut déterminer de façon fiable l'adhérence d'un véhicule automobile dans les domaines linéaire et non linéaire du comportement dynamique dudit 15 véhicule automobile. Avantageusement, on peut en outre obtenir une indication du niveau d'adhérence du véhicule automobile lorsque les limites de stabilité sont atteintes, elle est donc avantageusement mise en oeuvre lorsque ledit véhicule 20 automobile est en virage. D'autres caractéristiques et avantages de la présente invention apparaîtront plus clairement à la lecture de la description suivante donnée à titre d'exemple illustratif et non limitatif et faite en 25 référence aux figures annexées dans lesquelles : la figure 1 illustre un mode de réalisation du dispositif selon l'invention, et la figure 2 illustre un mode de réalisation du procédé selon l'invention. 30 Selon l'invention, l'estimation de l'adhérence est mise en oeuvre par la détermination d'une situation dans laquelle se trouve le véhicule automobile. Preferably, the calculation block of the adhesion according to a bicycle model further comprises another input incorporating the inertia of the motor vehicle (applied Mz). Advantageously, it is possible to reliably determine the adhesion of a motor vehicle in the linear and non-linear domains of the dynamic behavior of said motor vehicle. Advantageously, it is also possible to obtain an indication of the level of adhesion of the motor vehicle when the stability limits are reached, it is therefore advantageously implemented when said vehicle is in a corner. Other features and advantages of the present invention will emerge more clearly on reading the following description given by way of illustrative and nonlimiting example and with reference to the appended figures in which: FIG. 1 illustrates an embodiment of the invention; device according to the invention, and Figure 2 illustrates an embodiment of the method according to the invention. According to the invention, the estimation of the adhesion is carried out by determining a situation in which the motor vehicle is located.
A cet effet, on considère que le véhicule automobile est en mouvement, sur une voie de circulation ou autre. Celui-ci est donc mu selon une certaine direction linéaire ou en virage, possède une vitesse longitudinale non nulle, et peut être animé d'une vitesse (accélération) transversale non nulle. Selon l'invention, une première étape consiste à établir la valeur d'au moins un paramètre compris dans l'ensemble comprenant au moins la vitesse longitudinale, l'angle de roues, l'accélération transversale, et la dérive du véhicule automobile. A cet effet, des capteurs spécifiques peuvent être disposés, des logiciels de traitement mis en oeuvre, l'établissement de la valeur de ce(s) paramètre(s) étant connu de l'homme du métier. De préférence, on distingue essentiellement trois situations. Une première situation correspond à une dérive pure. For this purpose, it is considered that the motor vehicle is moving, on a taxiway or other. It is therefore moved in a certain linear direction or in a turn, has a non-zero longitudinal speed, and can be driven by a non-zero transverse speed (acceleration). According to the invention, a first step consists in establishing the value of at least one parameter included in the set comprising at least the longitudinal speed, the wheel angle, the transverse acceleration, and the drift of the motor vehicle. For this purpose, specific sensors may be arranged, processing software implemented, the establishment of the value of this (s) parameter (s) being known to those skilled in the art. Preferably, there are essentially three situations. A first situation corresponds to a pure drift.
Dans ce contexte, on établit par calcul ou par mesure la dérive du véhicule automobile. Ensuite on compare la valeur de la dérive établie à un premier seuil dont la valeur est prédéterminée. Si la dérive établie est supérieure au premier seuil, on considère que le véhicule automobile est en dérive pure et l'adhérence, dite mobilisée, est calculée par un modèle dit de frottement, correspondant à une totale perte de contrôle du véhicule automobile et dans lequel l'adhérence est un coefficient de friction Mu répond à l'équation suivante : Mu = JGamma/2 + Gammat2 Gammat max Où Gammat, et Gammal sont respectivement l'accélération transversale et l'accélération longitudinale (mesurées ou calculées) ; et Gammat max l'accélération transversale maximale, au-delà de laquelle un véhicule ne peut plus suivre la trajectoire imposée, les pneus n'adhérant plus suffisamment sur la chaussée. Une deuxième situation correspond à un certain niveau de dérive, de préférence dont le niveau est inférieur au premier seuil, c'est-à-dire une situation transitoire, illustrée par exemple par les cas de contre-braquage, dans laquelle on considère que la variation de l'adhérence du véhicule automobile provient plus du véhicule lui-même que de l'état de la chaussée sur laquelle celui-ci est en mouvement. In this context, it is established by calculation or by measure the drift of the motor vehicle. Then the value of the established drift is compared to a first threshold whose value is predetermined. If the established drift is greater than the first threshold, it is considered that the motor vehicle is in pure drift and the so-called mobilized adhesion is calculated by a so-called friction model, corresponding to a total loss of control of the motor vehicle and in which adhesion is a coefficient of friction Mu corresponds to the following equation: Mu = JGamma / 2 + Gammat2 Gammat max Where Gammat, and Gammal are respectively transverse acceleration and longitudinal acceleration (measured or calculated); and Gammat max maximum transverse acceleration, beyond which a vehicle can no longer follow the imposed trajectory, the tires no longer adhere sufficiently on the road. A second situation corresponds to a certain level of drift, preferably whose level is below the first threshold, that is to say a transient situation, illustrated for example by counter-steering cases, in which it is considered that the variation of the adhesion of the motor vehicle comes more from the vehicle itself than from the state of the roadway on which it is moving.
Si la vitesse de braquage des roues est supérieure à un deuxième seuil, ou si le signe de l'accélération transversale est opposé au signe de l'angle de braquage des roues (cas du contre-braquage), l'adhérence est calculée par un modèle dit continu dans lequel l'adhérence instantanée au temps Mu (t) est égale à celle calculée au temps t-1 : Mu (t) = Mu(t-1), quel que soit le modèle utilisé pour le calcul de l'adhérence au temps t-1. La vitesse de braquage des roues peut être calculée 25 par exemple par les mesures successives, de préférence instantanées, de l'angle des roues. Par ailleurs, l'angle des roues peut être remplacé par l'angle volant. Une troisième situation correspond à une situation 30 de limite. L'adhérence est alors calculée par un modèle dit constant dans lequel l'adhérence est fixée à 1. If the steering speed of the wheels is greater than a second threshold, or if the sign of the transverse acceleration is opposite to the sign of the steering angle of the wheels (the case of the counter-steering), the adhesion is calculated by a so-called continuous model in which the instantaneous adhesion at time Mu (t) is equal to that calculated at time t-1: Mu (t) = Mu (t-1), whatever the model used for the calculation of the adhesion at time t-1. The steering speed of the wheels can be calculated for example by successive measurements, preferably instantaneous, of the angle of the wheels. In addition, the angle of the wheels can be replaced by the steering angle. A third situation corresponds to a boundary situation. The adhesion is then calculated by a so-called constant model in which the adhesion is fixed at 1.
Dans ce contexte, on a Mu = 1 pour les paramètres ci-dessous . Si V < seuil3 , ou Si Gammat bicyclette < seuil4 et Gammat mesuré < seuil5*Mu(t-1) Où V est la vitesse longitudinale du véhicule automobile (mesurée ou calculée), Seuil3, seuil4, et seuil5 respectivement un troisième, quatrième et cinquième seuil, Gammat bicyclette l'accélération transversale calculée par un modèle bicyclette, et Gammat mesuré l'accélération transversale mesurée. Dans toutes les autres situations, l'adhérence Mu est calculée par un modèle de maximum défini par : Mu = max(mu bicyclette, mu mobilisée) Où mu bicyclette et mu mobilisée sont les valeurs de l'adhérence calculée respectivement par le modèle bicyclette et l'adhérence mobilisée telles que définies ci-dessus. Pour obtenir l'adhérence à partir de l'accélération transversale calculée par le modèle bicyclette (Gammat bicyclette) et l'accélération transversale mesurée (Gammat mesuré) on calcule le rapport entre les deux tel que l'adhérence Mu est définie comme suit : Mu = Gammat mesure / Gammat bicyclette si la vitesse de rotation du volant est non nulle, et Mu = Gammat mesure / Gammat max si la vitesse de rotation du volant est nulle, avec Gammat max l'accélération transversale maximale, définie par exemple par la connaissance du véhicule, des pneus l'équipant et de la chaussée. In this context, we have Mu = 1 for the parameters below. If V <threshold3, or Si Gammat bicycle <threshold4 and Measured gamma <threshold5 * Mu (t-1) Where V is the longitudinal speed of the motor vehicle (measured or calculated), Threshold3, threshold4, and threshold5 respectively a third, fourth and fifth threshold, Gammat bicycle cross acceleration calculated by a bicycle model, and Gammat measured measured transverse acceleration. In all other situations, the adhesion Mu is calculated by a model of maximum defined by: Mu = max (mu bicycle, mu mobilized) Where mu bicycle and mobilized mu are the values of the adhesion calculated respectively by the bicycle model and mobilized adhesion as defined above. To obtain the adhesion from the transverse acceleration calculated by the bicycle model (Bicycle Gammat) and the measured transverse acceleration (Measured Gammat) the ratio between the two is calculated such that the adhesion Mu is defined as follows: Mu = Measurement / Bicycle Gammat if the rotation speed of the steering wheel is non-zero, and Mu = Measurement / Gamma max gammat if the rotation speed of the steering wheel is zero, with Gammat max the maximum transverse acceleration, defined for example by the knowledge of the vehicle, its tires and the roadway.
Ce qui permet avantageusement d'éviter de trop sous-estimer l'adhérence pendant les phases transitoires et de ne pas trop la surestimer pendant les phases stabilisées. This advantageously makes it possible to avoid underestimating the adhesion during the transient phases and not overestimating it during the stabilized phases.
De préférence selon l'invention, le modèle bicyclette intègre également en entrée la valeur Mz (figure 1) égale au moment d'inertie appliqué au véhicule automobile par les efforts de freinage dus à une action de correction appliquée à la suite du calcul de l'adhérence. Grâce à l'invention, on peut ainsi déterminer de manière robuste quelle adhérence un véhicule automobile mobilise en virage. Cette donnée peut ensuite être exploitée dans des programmes de contrôle/commande dans le but par exemple de faire freiner automatiquement le véhicule automobile pour le stabiliser. En référence à la figure 1, le dispositif selon l'invention comprend un bloc 10 de calcul de l'adhérence selon le modèle bicyclette, dont au moins deux entrées sont la vitesse longitudinale V et l'angle de roues Angle roues du véhicule automobile. De préférence, une autre entrée intègre l'inertie Mz appliqué du véhicule automobile. Preferably according to the invention, the bicycle model also incorporates as input the value Mz (FIG. 1) equal to the moment of inertia applied to the motor vehicle by the braking forces due to a correction action applied as a result of the calculation of the adhesion. Thanks to the invention, it is thus possible to determine in a robust manner which adhesion a motor vehicle mobilizes during a turn. This data can then be used in control / command programs in order, for example, to automatically brake the motor vehicle to stabilize it. With reference to FIG. 1, the device according to the invention comprises a block 10 for calculating the grip according to the bicycle model, of which at least two entries are the longitudinal speed V and the angle of wheels Angle wheels of the motor vehicle. Preferably, another input integrates the applied inertia Mz of the motor vehicle.
Le dispositif selon l'invention comprend également un deuxième bloc 20 de calcul de l'adhérence dite mobilisée selon le modèle de frottement évoqué ci-avant et dont au moins deux entrées sont l'accélération longitudinale Gammal et l'accélération transversale Gammat du véhicule automobile. Un troisième bloc 30 permet d'assigner la valeur constante 1 comme valeur de l'adhérence. The device according to the invention also comprises a second block 20 for calculating said adhesion mobilized according to the friction model mentioned above and of which at least two inputs are the longitudinal acceleration Gammal and the transverse acceleration Gammat of the motor vehicle . A third block 30 makes it possible to assign the constant value 1 as the value of the adhesion.
La détermination de la situation dans laquelle se trouve le véhicule automobile est effectuée par un quatrième bloc 40 dont au moins quatre entrées sont la vitesse longitudinale V, l'angle de roues Angle roues, l'accélération longitudinale Gammal, et l'accélération transversale Gammat du véhicule automobile. Si le véhicule automobile se trouve dans une situation ne répondant pas aux critères des trois situations précitées, l'adhérence est déterminée par un bloc (non représenté, en l'espèce intégré au bloc de calcul 50) configuré pour calculer le maximum entre la valeur de l'adhérence calculée par le modèle bicyclette et la valeur de l'adhérence calculée par le modèle de frottements. The determination of the situation in which the motor vehicle is located is effected by a fourth block 40, at least four entrances of which are the longitudinal speed V, the angle of wheels Wheel angle, the longitudinal acceleration Gammal, and the transverse acceleration Gammat of the motor vehicle. If the motor vehicle is in a situation that does not meet the criteria of the three aforementioned situations, the adhesion is determined by a block (not shown, in this case integrated in the calculation block 50) configured to calculate the maximum between the value the adhesion calculated by the bicycle model and the value of the adhesion calculated by the friction model.
En fonction de la détermination de la situation dans laquelle se trouve le véhicule automobile, un bloc de calcul 50, comprenant des moyens de sélection, par exemple sous forme d'interrupteur multiports ou multiplexeur, assigne la valeur de l'adhérence Mu appropriée, en l'espèce l'une des valeurs suivantes : Mu(t) = Max(Mu mobilisé, Mu bicyclette), Mu(t) = Mu bicyclette, Mu(t) = Mu (t-1) , ou Mu(t) = 1. Depending on the determination of the situation in which the motor vehicle is located, a calculation block 50, comprising selection means, for example in the form of a multiport switch or multiplexer, assigns the value of the appropriate adhesion Mu, in the species one of the following values: Mu (t) = Max (Mu mobilized, Mu bicycle), Mu (t) = Mu bicycle, Mu (t) = Mu (t-1), or Mu (t) = 1.
Claims (7)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0759841A FR2925005A3 (en) | 2007-12-14 | 2007-12-14 | Tire and ground adhesion estimating method for controlling stability of motor vehicle during turning, involves selecting calculating model corresponding to determined situation of vehicle, and calculating adhesion of vehicle based on model |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0759841A FR2925005A3 (en) | 2007-12-14 | 2007-12-14 | Tire and ground adhesion estimating method for controlling stability of motor vehicle during turning, involves selecting calculating model corresponding to determined situation of vehicle, and calculating adhesion of vehicle based on model |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| FR2925005A3 true FR2925005A3 (en) | 2009-06-19 |
Family
ID=39476783
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| FR0759841A Withdrawn FR2925005A3 (en) | 2007-12-14 | 2007-12-14 | Tire and ground adhesion estimating method for controlling stability of motor vehicle during turning, involves selecting calculating model corresponding to determined situation of vehicle, and calculating adhesion of vehicle based on model |
Country Status (1)
| Country | Link |
|---|---|
| FR (1) | FR2925005A3 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103144637A (en) * | 2013-03-04 | 2013-06-12 | 奇瑞汽车股份有限公司 | Test method and test device for vehicle tyre-road surface adhesion coefficient |
| WO2017178722A1 (en) | 2016-04-13 | 2017-10-19 | Renault Sas | Device for tracking the path of a vehicle |
| WO2017203159A1 (en) | 2016-05-24 | 2017-11-30 | Renault Sas | Device for controlling the path of a vehicle |
| WO2018157999A1 (en) | 2017-02-28 | 2018-09-07 | Renault S.A.S | Device for controlling the trajectory of a vehicle |
| WO2021069810A1 (en) * | 2019-10-11 | 2021-04-15 | Psa Automobiles Sa | Method for estimating the road grip of wheels of a vehicle axle assembly by means of resistance measurement |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19515061A1 (en) * | 1994-11-25 | 1996-05-30 | Teves Gmbh Alfred | Stabiliser for four wheeled motor vehicles |
| DE10208815A1 (en) * | 2002-03-01 | 2003-09-18 | Continental Teves Ag & Co Ohg | Maximum coefficient of friction determination method for automobile calculates grip between tyres and road surface in longitudinal and/or transverse directions |
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2007
- 2007-12-14 FR FR0759841A patent/FR2925005A3/en not_active Withdrawn
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE19515061A1 (en) * | 1994-11-25 | 1996-05-30 | Teves Gmbh Alfred | Stabiliser for four wheeled motor vehicles |
| DE10208815A1 (en) * | 2002-03-01 | 2003-09-18 | Continental Teves Ag & Co Ohg | Maximum coefficient of friction determination method for automobile calculates grip between tyres and road surface in longitudinal and/or transverse directions |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103144637A (en) * | 2013-03-04 | 2013-06-12 | 奇瑞汽车股份有限公司 | Test method and test device for vehicle tyre-road surface adhesion coefficient |
| CN103144637B (en) * | 2013-03-04 | 2015-09-23 | 奇瑞汽车股份有限公司 | A kind of vehicle tyre-road surface adhesion coefficient test method and proving installation |
| WO2017178722A1 (en) | 2016-04-13 | 2017-10-19 | Renault Sas | Device for tracking the path of a vehicle |
| WO2017203159A1 (en) | 2016-05-24 | 2017-11-30 | Renault Sas | Device for controlling the path of a vehicle |
| WO2018157999A1 (en) | 2017-02-28 | 2018-09-07 | Renault S.A.S | Device for controlling the trajectory of a vehicle |
| KR20190123736A (en) | 2017-02-28 | 2019-11-01 | 르노 에스.아.에스. | Device for controlling the track of the vehicle |
| WO2021069810A1 (en) * | 2019-10-11 | 2021-04-15 | Psa Automobiles Sa | Method for estimating the road grip of wheels of a vehicle axle assembly by means of resistance measurement |
| FR3101946A1 (en) * | 2019-10-11 | 2021-04-16 | Psa Automobiles Sa | ESTIMATE OF WHEEL ADHESION OF A VEHICLE TRAIN BY MEASUREMENT OF RESISTANCE |
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